253 research outputs found
A system for electrotactile feedback using electronic skin and flexible matrix electrodes: Experimental evaluation
No full textMyoelectric prostheses are successfully controlled using muscle electrical activity, thereby restoring lost motor functions. However, the somatosensory feedback from the prosthesis to the user is still missing. The sensory substitution methods described in the literature comprise mostly simple position and force sensors combined with discrete stimulation units. The present study describes a novel system for sophisticated electrotactile feedback integrating advanced distributed sensing (electronic skin) and stimulation (matrix electrodes). The system was tested in eight healthy subjects who were asked to recognize the shape, trajectory, and direction of a set of dynamic movement patterns (single lines, geometrical objects, letters) presented on the electronic skin. The experiments demonstrated that the system successfully translated the mechanical interaction into the moving electrotactile profiles, which the subjects could recognize with a good performance (shape recognition: 86±8% lines, 73±13% geometries, 72±12% letters). In particular, the subjects could identify the movement direction with a high confidence. These results are in accordance with previous studies investigating the recognition of moving stimuli in human subjects. This is an important development towards closed-loop prostheses providing comprehensive and sophisticated tactile feedback to the user, facilitating the control and the embodiment of the artificial device into the user body scheme
Short- and Long-Term Learning of Feedforward Control of a Myoelectric Prosthesis with Sensory Feedback by Amputees
No full textPublisher Copyright: © 2017 IEEE.Human motor control relies on a combination of feedback and feedforward strategies. The aim of this study was to longitudinally investigate artificial somatosensory feedback and feedforward control in the context of grasping with myoelectric prosthesis. Nine amputee subjects performed routine grasping trials, with the aim to produce four levels of force during four blocks of 60 trials across five days. The electrotactile force feedback was provided in the second and third block usingmultipad electrode and spatial coding. The first baseline and last validation block (open-loop control) evaluated the effects of long-(across sessions) and short-term (within session) learning, respectively.The outcomemeasureswere the absolute error between the generated and target force, and the number of force saturations. The results demonstrated that the electrotactile feedback improved the performance both within and across sessions. In the validation block, the performance did not significantly decrease and the quality of openloop control (baseline) improved across days, converging to the performance characterizing closed-loop control. This paper provides important insights into the feedback and feedforwardprocessesin prosthesiscontrol, contributing to the better understanding of the role and design of feedback in prosthetic systems.Manuscript received October 19, 2016; revised April 2, 2017; accepted May 17, 2017. Date of publication June 6, 2017; date of current version November 6, 2017. This work was supported in part by Tec-nalia Research & Innovation, Spain, in part by FIK, Spain, in part by the European Commission under the MYOSENS project (FP7-PEOPLE-2011-IAPP-286208), and in part by the Ministry of Education, Science and Technological Development of Serbia under Project 175016. (Corresponding author: Matija Štrbac.) M. Štrbac and M. Isaković are with Tecnalia Serbia Ltd., 11000 Belgrade, Serbia, and also with the School of Electrical Engineering, University of Belgrade, Belgrade 11000, Serbia (e-mail: [email protected]; [email protected]).Peer reviewe
Multichannel electrotactile feedback with spatial and mixed coding for closed-loop control of grasping force in hand prostheses
No full textPublisher Copyright: © 2016 IEEE.Providing somatosensory feedback to the user of a myoelectric prosthesis is an important goal since it can improve the utility as well as facilitate the embodiment of the assistive system. Most often, the grasping force was selected as the feedback variable and communicated through one or more individual single channel stimulation units (e.g., electrodes, vibration motors). In the present study, an integrated, compact, multichannel solution comprising an array electrode and a programmable stimulator was presented. Two coding schemes (15 levels), spatial and mixed (spatial and frequency) modulation, were tested in able-bodied subjects, psychometrically and in force control with routine grasping and force tracking using real and simulated prosthesis. The results demonstrated that mixed and spatial coding, although substantially different in psychometric tests, resulted in a similar performance during both force control tasks. Furthermore, the ideal, visual feedback was not better than the tactile feedback in routine grasping. To explain the observed results, a conceptual model was proposed emphasizing that the performance depends on multiple factors, including feedback uncertainty, nature of the task and the reliability of the feedforward control. The study outcomes, specific conclusions and the general model, are relevant for the design of closed-loop myoelectric prostheses utilizing tactile feedback.Thiswork was supported by the German Ministry for Education and Research (BMBF) via the Bernstein Focus Neurotechnology (BFNT) Gottingen under the Grants 01GQ0817 and Grant 01GQ0810, and the European Commission under the MYOSENS (FP7-PEOPLE-2011-IAPP-286208) projects.Peer reviewe
Komu (pravo) zvoni? O pravnem in družbenopolitičnem izključevanju nedokumentiranih migrantov [For Whom the Law Tolls? On Legal and Sociopolitical Exclusion of Undocumented Immigrants]
No full textThe author examines the reasons for the undocumented immigrants’ vulnerability in their host countries. He claims that the main reason for this is the illegality of their residence on the territory of a particular country. The latter assumes the role of an all-determining legal status which, among other, exposes the undocumented immigrants to a high degree of arbitrariness in their contacts with host country frontline legal officials. Moreover, the social environmentn into which they come is often saturated with false claims about their intentions, deliberate perpetuation of negative stereotypes and widespread fearmongering against foreigners. Thus, the author argues that arbitrariness as a mechanism of legal exclusion of undocumented immigrants is often complemented and reinforced by mechanisms of their socio-political exclusion. The paper examines the characteristics of these exclusionary mechanisms and demonstrates how they complement one another. In pursuit of this goal, the author combines a legal-philosophical analysis of the relevant legal phenomena with a sociological and political science analysis of the language practices which form in reference to undocumented immigrants. Finally, in the second part of the article, he tests the theses and the methodological approach from the first part on the case of the Erased in Slovenia. He concludes by arguing that the exclusion of undocumented immigrants is a complex legal and sociopolitical phenomenon
Legality on the Frontlines of Administrative Decision-Making
No full textIn this essay, the author deals with the decision-making practices of frontline administrative officials. In particular, he examines how administrative circulars become the primary source of these officials’ decision-making norms, even when their content may be in contrast with hierarchically superior sources of law. The disposition of frontline officials to resort primarily to internal orders of hierarchically superior officials is explained as a consequence of the joint influence of several organizational principles upon their mental faculties. After introducing the problem and its relevance for legal theory, the author first defends the methodological approach to which he subscribes. Thereafter, he presents the central categories and organizational principles framing the institutional operations of public administrations. Finally, he provides a psychologically-informed explanation of the influence exerted by these principles upon the mental faculties of frontline officials which underpin the latter’s preference for the use of administrative circulars as primary sources of decision-making norms
MATIJA ANTUN RELKOVIC’S GRAMMAR
No full textThis work presents some relatively extensive account and review of one of the oldest grammars in Croatian or Serbian language. The speech is about A New Slavonic and German Grammar by Matija Antun Relkovic printed in Zagreb for the first time in 1767. Special attention has been drawn to those parts of the description which are specific for Relkovic for some reason or other. Some characteristics have been considered (e. g. graphic solutions, the description of ani- mate/inanimate category, the description of noun morphology and the use of nouns, the advantage of contrastive description and the like) and deficiencies of the applied description (influence of German and Latin languages, terminological awkwardness and poverty, inadequate conception of the dictionary, insufficient linguistic knowledge of the author and the like). This grammar has been compared with other older grammar books, especially with the first Croatian grammar by Bartol KaSic
The Non-Citizen. The Ins and Outs of Cittadini e no: forme e funzioni dell'inclusione e dell'esclusione by Patricia Mindus
No full textCitizenship has long been a heavily disputed topic, with the question «Who is the citizen?» generating much controversy both in academia and society at large. In her latest book, "Cittadini e no" (Firenze University Press, 2014), Patricia Mindus attempts to bring some much needed conceptual clarity to the debate. Having discerned three figures of the citizen which feature in the contemporary debate, the author proposes a general theory of citizenship, based upon Aristotle's treatment of citizenship in Book III of his Politics. This review briefly outlines the main characteristics of the proposed functional theory of citizenship and concludes with a critical comment regarding one of the arguments that Mindus advances
Le trasformazioni del diritto al tempo del Covid-19. Il caso sloveno
No full textThe paper analyses certain transformations in the production and application of the law during the Covid-19 pandemic. The analysis focuses on Slovenia, although its claims and conclusions can easily be generalized. The author first claims that the Slovenian government securitized public health – a move which gave it access to a broad array of exceptional measures, without having to declare the state of emergency. Secondly, he illustrates how the management of the epidemic was “administrativized”. The administrativization of government is seen as a technique of governing which shifts the centre of decision-making activities towards executive agencies and substitute statutes for sub-statutory acts as the principle decision-making mechanism. This technique is seen as particularly problematic when applied to the curtailment of fundamental freedoms
The State of Emergency in the Slovenian Constitutional Design
No full textIn this article, the author presents the essential characteristics of the state of emergency regime in the Slovenian legal system and provides a critical evaluation thereof. First, he presents the relevant normative framework of the subject matter by analysing all critical stages in the management of an emergency (the declaration, the state of emergency itself and its termination). Then, he focuses on what in his view are two most significant problems of the current regulation and provides critical comments on each of them. He concludes by calling for a major overhaul of the emergency management system
All the Earth’s legal children. Some sceptical comments about Nature’s legal personhood
No full textThis essay aims to provide an introductory account of Earth Jurisprudence as a legal theory and to examine its claims regarding rights of nature. First, two versions of Earth Jurisprudence qua legal theory are identified: a stronger and a moderate version, respectively. Then, the theory’s claims regarding the rights of nature are examined from the perspective of the general theory of rights. The idea of ascribing legal rights to Nature tout court is rejected, while it is acknowledged that sentient animals could be considered persons in law. Finally, the author suggests that instead of rejecting anthropocentrism, as Earth Jurisprudence proposes, the preservation of nature requires that more emphasis is put on human obligations in this respect
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